Categories

Archives

RSS

HP Pavilion f1703 Flat Panel Display Blackout Solution

I am not responsible for any damage you might cause to your monitor or yourself by following these instructions. If you open up your monitor case to this point, you will probably void your warranty.

CAUTION: There may be HIGH VOLTAGE present. Disconnect all power during disassembly. Inverters can generate high voltages.

If this repair is too daunting, HP has offered an extended warranty in this HP Support document. Thank you, tsmitty, for this link to HP Support. (Jan. 23, 2009: HP has discontinued this offer)

My HP Pavilion f1703 LCD Monitor suffered the same blackout symptoms as other posters in the CNET forum. After powering on, the display would go black after a few seconds. It was not the power supply in my case – I tried another working power supply with the same result.

It was also not a software problem, e.g., XP SP2, power management, screensavers, etc. In my case, it was a hardware problem, as I tried the monitor on a different machine with the same result: power on, brief display, then black. It also exhibited this behavior with no cable connected to the monitor.

I noticed the screen was faintly visible under bright light and realized that the backlight was not working. It seemed unlikely that the fluorescent tube would fail – I have had my Toshiba Portege 7200CT notebook computer on for 5 years, running SETI@Home.

Since the monitor was out of warranty, I decided to try to repair it myself. This is not a step-by-step procedure, but an general overview of how I solved MY problem with this monitor.

After reading the posts, it seemed that there must have been a loose connection on the circuit board that drives the monitor’s backlight. I especially noted gromit588‘s post about disassembly and followed the instructions. gromit588’s experience must have shorted some connection closed to fix the problem. I found that it did not help me, so I looked for bad (cold) solder joints on the backlight inverter board.

After a close inspection of the board, the bad solder joint was obvious. The bad solder joint on my board was on one of the coils – the bare pin on the coil was sticking through from the component side with very little solder on the pad on the circuit board. I resoldered it and that fixed the problem. There may be other cold solder joints at different locations on YOUR board. You just have to inspect each joint carefully.

This is a view of the monitor disassembled from the case:

This is the component side of the backlight inverter board:

This is the solder side of the backlight inverter board with the bad joint circled:

Close-up of the backlight inverter board with the repaired cold solder joint circled. Inspect the board for cold solder joints – they will be fairly obvious. It’s possible that the cold solder joints on YOUR board are in different locations on the board from the one circled here: (Jan. 23, 2009: If the cold joints aren’t obvious, I recommend using a 10x magnifier, or just reheat the solder joints on the components that have white glue holding them to the circuit board, see fig. 2)

Eight years later, and your article is still useful. My F1703 was made in September 2003, and has been in semi-constant use ever since. A few days ago, the black screen issue began to occur. I almost gave up after learning that the recall ended in 2009, but decided to give your solution a try before junking the screen. The problem on mine turned out to be a very hard-to-miss cold solder on one of the toroids. I can’t thank you enough for your excellent article, as well as all the time and research you have spent for others on this issue.

I found a F1703 cheap and bought it, they told me it was working. Guess I should have had them turn it on. Anyway, I found some bad solder joints and repaired them, but I am still having some problems with flickering, lines, faded, etc. I have one bad cap, C102, which I can replace as soon as the stores open tomorrow, but there is also one SM cap that is blown on the other side, C114. Any help on the value would be greatly appreciated.

You are awesome. A few weeks ago I was given a HP F1703 monitor with the 5 second blackout problem. Followed your suggestion re resoldering the coils and, lo & behold, it now works. Bad solder joits appears to be a common problem with this monitor. Thanks very much for posting it.

I just discovered that the display in the F1703 is exactly the same as in a 1702 monitor. If you can find a black-out-defective F1703 and a punched 1702. you can swap out the displays and you got yourself a working 1702 with F1703-display in it.

R128 is a 2W 1 Ohm 5% resistor in the +9.2V 200mA supply. It’s located on the LCD Control board & is close to D184. 2002 vintage. It’s failed probably due to a due to a short. Check C160-163 and elsewhere for shorts.

Leslie,
I have been running this power supply on the f1503 now for about 2 years, I opened it up last week and had a look, nothing is showing signs of running too hot, but you are right it is probably a ticking bomb and will eventually fail.

I have found another f1703 at my local auctioneer and hopefully will win that one for $10 Aussie – it powers on but no picture, sounds like the inverter board. Hopefully the joints on the toroid coils are dry or a few bad caps, nevertheless I now have 2 of these monitors to work on both for under AU $25…with parts and power supplies.

(continuing the story from post 344)
The monitor has been functioning since May. Some weeks ago, the kids started to complain about having to use the on/off button repeatedly before the monitor would stay on, and finally it would not switch on any more. My wife has bought them a new one, but after some trial and error I seem to have the f1703 back to work again: by setting the brightness to its very minimum before I switch the monitor off.
Looks like the monitor is reaching the end of its life, but I have spend so much time in trying to repair it, I’m not letting it go yet…

Todd, I thought the output voltage of the AC supply was around 12V. Running it at ~18V-19V might work for a while (your “fair amount of tolerance for input voltage”), but you must see why things start to fry after a while.

I inadvertently plugged the power adaptor from my N610C laptop (18v DC) the night the f1703 inverter board blew, this subsequently blew Q212 and Q211 I will replace these, will also replace Q210 & Q209 to be sure. R128 is fried and not showing any resistance, all fuses are ok?

Looking at the f1503 I am using, the power adaptor is rated at 19v @ 3.16A DC. I know it is the wrong adaptor, however it works!!

It would seem the f1503 board has a fair amount of tolerance for input voltage. Secondly, the f1703 only had 18v @ 3.61A, I recall it turned on and then a “That Smell” come from it (Inverter transistors).

Would it be a fair call to say the f1703 had an underlying issue when I run the 18v into it.

Ok, someone in my family plugged a power cord into the power out for the speakers. Now the monitor won’t work. I opened it up and low and behold the resistor behind the power in is fried. I’m trying to replace it but it’s so burnt up that all the markings are gone. I’m trying to find out what the Ohms is on it so i can go to Radio Shack and get a new one to replace the burnt one. Can anyone tell me what it is? I can sort of see it in the second pic but can’t make out exactly what it says.

Thanks man. That was exactly what’s wrong w/ mine. It was a different cold solder join w/ one of the coils. When I did the visual inspection the first time, I did not use any magnifying glasses and I missed the d*mn cold solder joint. Finally I took your advice and used a high power magnifying glass and spotted the bad joint within one minute. Most high tech equipments are fairly reliable today, except most of them fail on the most basic electrical issue – cold solder joints. That’s how I fixed my expensive Sony TV, dehumidifier and the list goes on and on.

I picked up a F1703 for $5 at a yard sale. It has the flash to black screen after 2 seconds of good display. Tried to solder suspect joints but problem persists. My circuit board was mad by BenQ 55L0U02001 and has a completely different layout of components. Any one else have his board?
Also I’m using a 12V 3Amp Power supply will this cause problems?

Very helpful, this! Resoldering the cold joints worked for a couple of times, but now, after about a year and a half, I ran out of badly soldered joints. There were no obvious defective components. I removed and checked the capacitors, but none of them were leaky. Still the screen blacked out after a couple of seconds.

What did the trick now was resetting the monitor to factory defaults. I found the suggestion on the (closed) cnet-forum f1703-topic (post 392). You need to connect the monitor to a computer before the menu-button will work. Although the screen is black, you can see the menu when you look carefully.

Went through it coupla more times… re-soldered a few more joints although I couldn’t find anything more that was suspect.

Now, however, the monitor doesn’t show that small message anymore, but it does a vertical flicker (cannot make out what might be there)
and the screen has a void (not black) for about an inch on the right side. In about 5 seconds, it shuts off.

Could some component be bad? Some, but not all of the small purple “cans” have been siliconed …would these be suspect?
And there are 2 blue resistors (I guess that’s what they are..look like miniature pillows), one of which is siliconed, the other not.
These are the same as what’s shown in your 2nd picture.

I’ve taken the f1703 apart and re-soldered the (4) torodal coil connections twice. Still doesn’t work….however, I’ve yet to look closely at the other siliconed component joints
I get the small rectangular warning message. “PC entering power saving mode”, then the monitor’s yellow led light comes on and the screen goes black.

This monitor is one I gave to a friend and was working fine for a coupla months; prior to that it was used for about 3 years without incident. I don’t know if that message appeared for him or not, he just said it went black after about 2 seconds.

great help for the f1703, but I am having the same problem with the f1730. Now I have fixed the backlite on about 5 diffrent f1703’s and replaced transistors on 2 others. (thats when you get the flashing yellow power lite.) I haved looked and fixed all the bad joints I could find. Now with the f1730 the backlite inverter board is totaly diffrent then my experiences. If some one could point me in the right direction with this one, that would be great.

Thanks for the useful Guide. I never would have got the HP 1703 apart without it since dismembering the beast is not covered by the HP F1703 Service Manual. These monitors were made by AOC for HP. I fear the one I have is suffering from a little aore than dry joints on the toroidal chokes L102, L103, L201, L202 like your monitor. The 2SC5706 inverter transistors mentioned by Randy Bay are Q209,Q210,Q211,Q212[2SC5706-P-E].

The two inverter transformers [PT201,PT202] are 80LL17T-9-LS and I expect a scrap monitor is the only source of them unless you can get them from AOC. Note that high voltage output is across pins 7 & 9 of these transformers so keep fingers and multimeters clear.

The sequence for testing the inverter board is firstly check CN101 for 12V if no 12v then check the power adapter. Check the on/off signal with a scope. If none check interface board. Check U201 Pin 9 for 12v If none relpace F101. Next check U201 Pin 1 for sawtooth waveform. If none repklace U201. If there’s a sawtooth wave then short C207 and check U201 , pins 7 & 10 for square wave output. If no square wave THEN check Q203 [AO4411 SO-8],Q205 [PMBS3904/PHILIPS-SMT(04],Q207 [PMBS3906/PHILIPS-SMT(06] & Q204,Q206,Q208. if faulty replace. Check that the square wave has a 90% duty cycle minimum. If not check Q209,Q210, PT201, C213 & Q211,Q212, PT 202,C214. If the square wave is OK then check the feedback circuit [R232………..R233]. If No 1.8V, 3.3V, 5V Output, then check CN101, the wiring harness, for 12v If ok start checking U101.

Note – To do this you need a PC, multimeter, oscilloscope and preferably the circuit and board layout diagrams. Some of the devices are surface mount components and you’ll need to have experience ibn dealing with these.

If you are not experienced in servicing don’t attempt to fault find unless you are prepared to send your monitor to the recycling centre. You do this at your own risk as there are high voltages involved.

Resolder all cold joint is just one small step in troubleshooting,
the cap, resistor, transistor, diode etc need to check with testmeter
in order to confirm it working or not just by looking it may look fine but it doesn’t mean it working.

I have a broken f1503 that was given to me by a friend for free, and I was thinking how nice it would be in my car, seeing as it runs on 12v dc natively… but I can’t seem to get it fixed. The caps look fine, no bulging or leakage… The backlight itself works, but it powers down after ~1 second. I tried resoldering the toroids, transformers… but it didn’t seem to fix the issue. I’m running it off a 12v 5A psu, so power is not the issue here. I’m considering wave resoldering the whole board, seeing as none of the joints look cold. There is no visible physical damage to the board itself, ie, burned, discolored marks. I don’t know what to do about this really. What are the possible failures that could cause this problem? I could just replace the whole thing, but where’s the fun in that? I would like to take a look at a working board if at all possible…

I have an lcd screen hp f1523, and the power board is 715L1034, i know that is not de same, but i think it is simmilary. I dont need to use the backlight of my lcd (it is to build a multitouch), i only need thaht the screen will be recongnized by the computer, and lcd module work.

If i delete the zener (it is burned), and the capacitor (is bigger than normaly), do you think my lcd module only will be work? i dont need backlights.

thank’s for the futures responses, and many sorry for my bad english speaking…
thank’s to all…

Thanks to all,your insight and comments greatly appreciated. Found my monitor in a thrift store for $15.00. My monitor was doing the typical fade to black after about 5 seconds. Found a few questionable solder joints on my board and one overheated and cracked transistor. Repaired joints and replced one transistor, still had same problem. Replaced the other three transistors and problems corrected, works great now. Found transistors on ebay @ $4.99 including shipping.
Leslie; thanks for providing this forum.

f1703 heres my issue. Blue LED comes on for anywhere from 3 to 10 seconds, I get a humming noise for a few more seconds then a flash and pop thru speakers blue light again and starts all over. HP said they would send me a new one free of charge a year ago, still haven’t got it yet. I called several more times and was told that it was still in processing. well it cleared up and worked fine doing nothing, so I forgot about it. I called them a few days ago and was told that they are no longer offering replacements. AND this ticks me off the most, they have no record of any contact to them even though I gave them dates & the persons name who I spoke to. A-hole company has lost another customer. I tried resodering the coils and capisters look fine still no luck. Time for a new computer I guess 5 years is a good run the way things are so cheaply made these days

Followed your advice, I re-soldered the 4 coils, my HP F1703 is up and running properly again! No more black/dead screen now. I had the same problem with my HP F1903 a few months back, had cold solder joints that took out one of the four display backlighting power transistors. I found them on eBay for $6.00 a set, replaced them all and repaired the cold solder connections. Thank you all for all your advice here!!!

OOOPS! I was in error. I’m looking for the value of inductor/choke or filter that’s located on “L110″. My pcb number is 715L1091-1-2 so I’m assuming it’s an early model as later models didn’t have this component.

Thanks to all the people contributing to this issue. The photos were a MAJOR help. I only had to reheat one joint that had become cracked from what seemed to be heat build-up. Picked this monitor up on the curb and now it works great! I also punched a few extra holes in the heat sheild behind the inverter to see if that might releive some of the heat. If it fails then I’ll tear down the old joints and repair them fresh. Thanls to all the contributors to this issue especially whoever put the great photos!!!

Yes this simple guide make me so happy with my HP Pavilion f1703. I bought this LCD from recycle computer shop at SGD100. It having a flickering after an hour on. With a try following this site I make that flickering gone.

- – – – –
I bought a HP f1703 from a man I found on the internet (weird guy..!)
He had the screen connected to a computer, I gave it a quick check and decided to buy it for 40 Euros.
At home installed it on my pc and had it running for one week. Then it started to fail.
The screen kept turning black, after restarting the screen it went back on, and after a few seconds it turned back to black…
+ + + + +
Thanks to this guide for fixing the power board its running for days :D:D
Excellent work !! Thank you

Something I found while hunting for clues –
Switch Mode power supplies as used in these monitors are susceptable to power spikes or low power situations.
If your monitor blacks out during the same time of day – This can be the cause.
Problem is most likely an overheating fast power transistor that tries to regulate the power required.
Large filter capacitors can dry out – causing excess ripple. Now bad capacitors are definately a “ticking clock” used by manufacturers to scrap older equipment.
This site may help if other repairs don’t do it for you –http://www.repairfaq.org/sam/smpsfaq.htm

Like others, I had a problem with my 2-yr-old HP f1703 blacking out or just not ever lighting up when the computer was started or the monitor was plugged in. Sometimes the blue light of the “on-off” switch would flash a couple of times, but nothing else.
Per Mr Wong’s instructions, (with the disassembly recommended by gromit588) I soldered the whited-glued components, plus a few others that looked bad. I now have a monitor that appears to work perfectly again!!
Thank you for your logical and well-explained approach to what should be HP’s problem, but appears to have been abandoned by them. You saved me much time and money, and my sledgehammer is back in the garage where it belongs. Mr Wong, you are a legend! THANK YOU!

Followed the directions, and now it works! Used a $7 5 piece Radio Shack soldering iron set. Only let it stay powered for about 30 seconds to test it because I’m using a 12v/1amp power supply in place of the 12/4 and that would spell trouble down the road … but I’m confident it works fine so I’m happy and will just keep using my Samsung 15″ lcd till I get the right power pack. Just curious though why EVERYONE has a bad solder in the same place? Almost seems like an intentional and concerted effort.

My Dell monitor Has exactly the same problems as David’s above. Seems to be an overheating problem. Will be fine for hours – then go bright for 5 seconds – then screen goes black. Power light stays green.
I’ve replaced 4 C5707 transistors, and a thermal fuse in there – but problem is exactly the same.
Bad Caps in supply ? or one of the main power transistors on a heatsink that looks a bit hot – P7NK802FP . – This will be my next attempt – all power transistors. Thanks for great article.

Thanks for posting this. I fixed 2 monitors using your guide. The first I found in the trash. The second I picked up on eBay for $10. They are both side-by-side now on an old Mac Centris 610 (20mhz 68040!) each running at 1152*870 resolution. Lots of pixels per $! Thanks again!

It is not only the joint I circled that could be bad. Any of them could be bad. That’s why I recommend using 10x magnifier to check all the solder joints.

If there is no power, check the solder joints for the jack where the power cord plugs in. Maybe it is shorting. Try flexing it and see if you can see a break in the solder joint. Or just reheat the connections for the jack.

I’ve resoldered the join identified in your article and the monitor worked for a good while. The problem came back again, so I tried the same thing and now the monitor doesn’t power up at all – no light on the power button when plugged in. Have I killed it completely or is there something else I can do. thanks so much for your help. Jono.

Thx so much for this im only 16 years old and i opened this up myself, fixed it like u said, and now i can continue playing my XBOX 360 on this monitor. The only reason i had the guts to open it up is cuz i’m in the engineering program at my high school and I desided maybe i’d give it a shot. THANK YOU!!!!

I implemented the solution and it worked perfectly. It was a bit difficult inspecting the soldered connections. Using two magnifying glasses together it was still difficult to spot the faulty connection. Ultimately I resoldered the 201 connection mentioned in this article. I then followed the Corvallis engineer’s suggestion to inspect all of the cold solder joints, and I touched up the solder on one suspect connection. Then after thoroughly brushing off the board and reassembling the system, the monitor worked great.

Thanks everyone for your input, and for providing the solution. It’s great to have two monitors now.

Mr.Wong,
I am sooo not a fixing person. I need a big red arrow to be there when I open things up. I did follow your steps and I noticed your solder is predominately in the middle and mine is on the sides. 2 of the 4 coils have little metal “rings” around the pins (the ones that had the black solder as they go thru to the front of the board. Do you think that might be the connection issue?

I acquired another of these monitors, with an additional problem. I wanted to add an addendum, and another fix for this same problem. In addition to the solder joints on the 4 toroids, I looked and found other cold solder joints, dull gray, I completely removed the solder with Solder Wick and resoldered all of those connections. The problem with the backlight persisted. In addition to the Solder Joints, the 4 Driver Transistors (2SC5706) were replaced, THEN the Monitor Worked and has stayed working. These Transistors are about $1(USD) each. I bought them off of ebay. You might want to add this info to your repair blog.

I want to thank you for your posting the fix for the HP F1703 LCD Monitor. I work for HP, but not in the computer or monitor segments of the business. An engineer gave me a personally owned F1703 that had the backlight problem. I Googled it and found your page. I fixed the monitor and after a few months the problem reoccured. I had just touched up the solder with a little fresh solder. I went back and totally removed the bad solder and used a little flux on the area to be resoldered and resoldered all of the inductor joints. It’s held up well. I have used the repaired monitor for months. I bought a second “As-Is” F1703 off of EBay for $25, I did the required resoldering and the backlight worked. The Monitor image did not come on. I dug into the monitor and found that the LCD connector above the mainboard had become disengaged. Apparently when the lamp power supply failed the previous owner forcibly struck the top of the monitor, fracturing the hot glue that had been put there to secure it. I rengaged the connector and hotglued it back into place and now I have another fully functional monitor. Thanks for taking the time to document this. I have a nicer monitor in my guest room as a result.

Thank you so much, I had no idea what parts they were–They do have numbers on them, and I googled them to death, but I was unsure of what part I was looking for, exactly.
I was thinking that as well–If nothing else, I can buy a trashed monitor and salvage the transformers from it.

JonelB – PT201 and PT202 are transformers for the inverter. I don’t know the specifications for them. If there are any numbers on them, you can google it or look at Digikey or Mouser, otherwise, you’ll have to find another broken monitor for parts.

Well, thanks to your pictures I know that it is, in face, the Yellow PT 201 and PT 202 are the peices on the board that are broken, not the solder–Thanks!
If you happen to know where to get replacements(this is my first repair), a link would be appreciated.

Hello,
I have a Westinghouse 19″ LCD that I bought used (not working…very dim picture) off of Ebay, with the intent that I would just change the backlights on the thing and it would work perfectly. Well, upon tearing the thing apart, I can’t even FIND the backlights, much less replace them. I did, however, find a cold solder joint and resoldered it well. Turned it back on and still same thing….VERY dim picture, can barely see it and only with a flashlight! Any chance that if I resolder ALL the joints on the coils (BTW….what is meant by “coils”?), that it will work, or are the backlights burned out? Can’t find much of anything on Westinghouse monitors or parts, but the board matched up with Viewsonic. Any ideas? Thanks for any help!

I never measured any voltages because I didn’t have any repair manuals. I would try to just reheat the solder points of the components that have the white silicone glue holding them to the board – see the second photo.

I examined the inverter board for my F1703 with a jeweler’s loupe and could not find any broken solder joints. I managed to find a replacement board, but with it installed, the monitor still shuts off after about four seconds. I can’t believe both boards have the same defect. Where can I measure the voltage to determine whether the board(s) are operating?

Thanks for your site, I’ve been putting off the repair for some time, I finally attempted it this morning, less than an hour and I have someones discarded monitor working! Didn’t see any obvious solder joints but retouched all coils and some connector joints. Again Thanks!!!

Hey man dude I just fixed my dads monitor he got 2 years ago with his piece of crap HP computer I told him not to buy. He was throwing the monitor away I was like “na ill take it” and now I fixed it he wants it back ;-). I didn’t think it should be something hard to fix but thanks heaps for your info mate its nice when people share there expertise.

OK, I’m back for a second round of repairs. I found this site in September of 06 when my 1703 was having same problem. The repair worked flawlessly for over two years but the problem has now resurfaced. Looks like I’ll be opening her again.

I could just go out and buy a new monitor but personally I love the display on this one so I’ll stick with her as long as I can. Will post back again when I complete the repairs a second time.

Hello Mr Wong : I am amazed at the amount of information that one could get out of this site , thanks for your great help and expertise . I have a HP 1703 , will like to know how to check the caps , how do I do it besides looking at them, also the transformers , can I use an Ohmmeter, and what would be the setting to chk. the trfrms. What kind of soldering should I use, just bought a SA 1000 soldering station, with no manual, need to know what temp. Any help would be very much appreciate it . Thanks Ray Roman

I just fixed the f1703 last night. I followed the instruction and pictures given here and took me about 1 hour. I didn’t see any obvious problem with the solder but again i won’t really know if there is one. I proceed to solder the one that was id here and two others that I though might be problem. Put it back together and it has been working since last night. it used to go out every ten minutes. thanks for sharing. this enable us to save money and put less on the landfill.

Thanks. I just fixed an HP f1703 monitor by resoldering the coil connections. Apparently, the supplier did not chemically strip the insulation from the coils magnet wire. This monitor showed 5500 hrs of operation, but eventually the connection came apart. Just to be sure, I hit all the coil connections with the soldering iron.

However, I goofed. I initially used unleaded (RoHS) solder, which resulted in a dull gray connection. Not good. I had to solder suck all the solder from the initial connection and replace it with the older tin-lead solder.

I have 2 f1703’s both with the same black out problem. I’ve tried the suggested methods with no luck so far. I see no bulging caps and no obvious cold solder joints. I’ve tried resoldering the coils and transformers I can identify and they both still black out after a few seconds. I’d love to send both of these backlight boards (just the boards to save on shipping) to someone with the tools and know how to fix them and return them for a reasonable fee. ANYONE WANT THE JOB?!?!? PLEASE!?!?!

YES! mados123 nailed it. My HP FP17 had no power LED lit. After reading this forum I checked the 3 caps with bulging tops and sure enough, green power LED and a beautiful screen. 2 1000UF and 1 470 UF.

With my HP FP17, it was specifically the capacitors as well. I repaired the joints first and that did not make a difference. Then replaced three bulging capacitors and viola! Thanks for the great website and info!

HOW DO YOU KNOW WHICH SOLDER POINTS ARE BAD I TOOK MINE APART TODAY JUST TO CHECK AND THEY KINDA ALL LOOK THE SAME I HAVE NEVER DONE ANYTHING LIKE THIS BEFORE BUT I’M READY TO TRY RATHER THEN TRASH IT ….ONE MORE QUESTION IS THERE A SPECIAL SOLDER TOOL I SHOULD BUY OR WHICH ONE WILL WORK BEST .THANK YOU FOR ALL YOU HELP

I rescued an f1703 flat panel on it’s way to the trash at work a couple of years ago. Last Sunday, I finally got around to cracking it open and resoldering the transformers on the power supply board. (I didn’t touch the toroidal inductors, but I will if it dies again.) It works beautifully! First I wicked off all the solder on the transformers, then I cleaned the extra flux off with alcohol. Finally, I carefully resoldered them, and presto! What a nice display for the price!
(The transformers are the flat, squarish metal things on the right side of the board, near the connectors with pink wires)

I Know, I Know — This sounds very much like Fun but it Really solves the problem! — After drinking a few glasses of Champaign,Didn’t it help make you feel better ? It Sure made me feel better to know that All that money I paid for a New Monitor did not go to waste !
I’m just glad I was able to Help some other Son of a Gun feel just as Good as I Did ! …. Al Einstein: (porsche.lover@live.com) Once You Open up a can of Wupp-AzZ on that Monitor & have a couple strong drinks, All your problems just Melt Away & and You feel Real Good TOO !

To OPEN the L1702 Monitor casing after removing the screws…..This I always found works in Ever senareo… Lay a large towel or a small carpet segment on a stationary work/table area…Next,After removing the screws you will notice that the casing still will not want to separate from the two halves so … With a little effort raise a large wooden chair over your head or with a 10 pound Sledge hammer in hand,Smash that damn monitor all to Hell! — You have just Fixed the problem… Open a bottle of Champaign & Celebrate!!

I have a similar problem with an L1702, but I’m much more novice than you guys. Are there any instructions on how to disassemble the monitor? I’m gutsy enough to try it, but after removing the only visible screws it remains intact! Any help would be greatly appreciated. Thank you.

My f1503 pc board looked completely different than the one pictured. Not only that, but all the solder joints looked perfectly serviceable. I went ahead and reworked them anyway, especially the coil connections. Took me a little while, but it worked for about 20 minutes.

Now, I have to say that the monitor will not even turn on. Oh well. Worth a shot. Now it’s trash time.

I have the same screen shown in the pictures which doesn’t turn on and I measured the power in the adapter and it says 12.2 V which is good but in the board it decreases and I didn’t see anything burned in the board. please provide me whith information to solve this problem. my best wishes to everybody. thanks

Yep, Same here, 2 cold joints on the coils. Also found one of the surface mount transistors that had an unsoldered leg. Quick touchup and Darlene’s monitor is as good as new. ( I also reflowed all the coils- just to be sure.)

Leslie,
Wish u had more insight on Viewsonic. I am working on a VA1912WB. Replaced two caps 220uf,25v and 1 1000uf,25v. Resoldered all joints. Same problem, Green power light blinks.Screen black.
I did repair a Gateway tft 1960 by re-heating solder joints. Caps were bulging slightly. Went ahead and replaced. Works great.

I’m working on Model# P9620A.The backlight inverter board is defective.Q204 has burnt a hole in the pcb.Where can I purchase this PC board from?
Thank You,
Steve Flowers
Service Tech
Needle in a Haystack
Audio/Video Service
Phone:614-488-2622

Mr Leslie Wong, thank yuo for your answer. I have done all in the post168 mentioned actions before I asked for a help. All of the solder joints visually looked unaltered. All joints were examined by tester, and seemed like normal.
Is there some possibility to download an elektric circuit diagram from somewhere? It would help to identify in which part the corruption is, and the biggest part of questions would bee answered.

Great Fix! Once i got my monitor apart it was very obvious after some moderate examination which solder joints had gone cold(bad). I had 2 bad joints on my board both were with the coils (components L201 and L202 on the board). In an effort to prevent future cold joints i went ahead and re-soldered all 8 of the joints in connection to the 4 coils (L201, L202, L102, and L103). Closed it back up and left it on for about 15 minutes with no issues. took me about 30-45 minutes

Great post. Took mine apart, soldered the joints (all of them) and tada. Never would have thought of this, even after it was apart, did not see cold joints and have been doing electronic repair for thirty years includng microwave communications. Great catch. I know this has been going on a while as I see, first I heard of it not sure I would ever by HP again because of this and thier response. Not very good customer quality care. Makes you feel like you bought it at a swap meet.

thanks for the reply Mr. Leslie.wong,
I have tried using a magnifier and also a jewelers loupe i did not see anything but i went ahead and heated all the solder connections,and still only the top half works.Is there anywhere you know of that might have replacement parts;boards ,bulbs ect. ? the only thing HP offers is the power cord and cable.Also should i be looking at anything else besides solder points?

Just wanted to say “Thanks”. I had the problem where the screen would blank out after a few seconds. I re-soldered all four coils and it works great now. None of them looked burned and the solder looked solid but I heated them up and added a bit more to them. Thanks for keeping this blog page going.

Im haveing the same prob I have a Hp pavilion f1703 flat pannel and i can see the pic just fine on the screen for a few seconds then it goes blank. I think it might be a loose connection between the back light and the bourd. Should i just replace the back light or try and solder it?

Hi I have monitor and its has the same black out problem.
And every time I turn on the computer I can see the bios screen for second and next thing I see is Xp lording for second and the desktop for second.
When I unplug the video cable and plug it again I can see the desktop and the light go off.

So I resoled old the cold joint and now I got another problem when put power supply to the monitor I can see the blue light coming and its go after two second. Now I cant see anything. And if I plug power supply I cant see the light. Have to wait 5 mints and connect it to power supply I can see the light and go of.

Thanks for the guidance on fixing my Flat screen. The PCB was a completely different layout but a gentle waft of the soldering iron over the connections in the invertor area(none appeared to be dry)both top and bottom of the board did the trick in 20 minutes. Great stuff – thanks

I have a problem with the 1703. The monitor starting going on and off and on and off and I smelt something (like burning). Anyway, I just resoldered the coils and tried it again, and I’m still getting the same on and off and on and off (every second).
Any advise! Thanks Fred

Hi!
I have successfully repaired an F1723 with the “Power light flashing” fault. I turned out to be a failed 1000uf 16Volt capacitor. The capacitor was domed out and squint.
A more complete account is on my web link.

Leslie you must be a beautiful person ! Your blog is just great ! It’s so nice to find such unselfishness !
As a retiree careful with his money, you allow me to use a flat screen display ! Thank You.!!!
I found this f1703 at the curb discarded as trash. Without knowing about its poor record,I took a chance and decided to fix it.Then I found your forum and repaired it very easily by re-soldering all 8 coil’s terminals.
Also my thanks to all the people that provided additional advise. Keep up the good work ! Al

Your assessment of the problem was right on. I found two bad and one suspicious solder joints on the inductors. To be safe, I resoldered all eight spots. My monitor works fine now. Thank you for your help and also, thanks to Gromit588 for the disassembly steps.

Wanted to say i was having the same problem with the blacking out and used the flash light and seen i could see my Deck Top so took it apart soderd the the joints and put every thing back togeather and bam no porblem yet thanks for the tips

See this link for full details on how to disassemble the AOC LM729. Much searching online has led me here for that model. I’m really just redirecting to a post I made with the full disassembly instructions. Mr. Wong – asking you to review and say if the disassembly for the F1703 is anything like it. You’ll also notice that the insides look much alike.

I read your solution and have taken my f1703 apart. I found that one of the coils on the circuit board (one of four coils) had a bad solder with the wire loose at the solder joint! I am borrowing a soldering gun and will let you know how it works out. Thanks for the great pictures. It really helped!!

G’day Leslie – thanks for a great blog. I’ve tested my computer on another display and it’s working perfectly. I’ve also eliminated the cable as the problem. There are two boards on the F1703 – one is for the backlight HV converter, the other processes the video and feeds the data to the screen via a multi-core cable. The backlight board is a later model than that shown in your photo – it uses SM components on a multi-layer board. A few connections are made through to the back of the board, such as the toroidal coils and the electrolytic caps. I resoldered all of these, but since they looked OK to start with, nothing changed. As I said, the backlight is working just fine. Next I tackled the video board. I renewed a few 4.7 uF electros which had high (9 ohm) ESR, but to no avail. Rather than attempt a full scale troubleshoot on the video board, it would probably be quicker to find a good 2nd -hand board from a monitor repairer, or a new one from HP. However, other readers of this blog might have experienced this problem and offer some suggestions on how to proceed. Thanks again for your comments.
Cheers
Rob

I recently encountered exactly the same problem with my F1703. Following a “we can’t help you” response from HP Customer Care I discovered your blog on the issue. Following gromit588 and your instructions, I revealed about 7 badly soldered joints on the backlight PCB. I resoldered them all, and hey presto, good as new. Many, many thanks.

My HP F1703 backlight seems to be working fine. Instead my problem is dark bands which drift down the screen, and a broken up picture – looks a bit like loss of vertical sync, but the display is torn horizontally too. The problem occurs at start up, but after say 10 minutes it disappears and the display is normal. This suggests the fault is in the signal board rather than the backlight board. Anybody had this, or know how to tackle the fault? The board P/N is 715L1006-1A-HYD.

Rafa, is the burnt resistor on this board – http://www.lesliewong.us/images/monitor/2.jpg? I can get the values of the resistors from the photo. If nothing else looks bad, all you can do is replace the resistor and see if it works.

After following your directions above I found that the problem is not a cold solder, but a burnt resistor. It has cracked and leaked, but because it is burnt it has turned completely black, so I cannot identify what type of resistor it is, could you help me? And I heard that if a resistor is burnt it might mean that another part is non functional do you have any idea what could possibly be?
Thanks!

This is a good introduction to soldering. I don’t think you need to remove the silicone unless it’s really blocking the connector. It’s there to hold the components onto the board when it is assembled.

You really just need a 40 watt pencil soldering iron and a wet paper towel to clean the tip. To resolder the coils, just touch the tip for a few seconds to the connection long enough to reheat the solder so it will flow around the connector.

Look at this NASA soldering requirements guide. The photos labeled, "PREFERRED SOLDER SIDE FILLETS (PTH/NPTH)" and "ACCEPTABLE EXPOSED BASE METAL" are what the solder joints should look like. The photo labeled, "UNACCEPTABLE ADHESIVE INCLUSION" is what causes the problem.

Thanks for the reply. The part is on the inverter board and has three contacts. A friend thought that it was a transistor. It is a little rectangular part at the edge of the board.
I am considering to venture into the soldering. Have to buy the equipment and learn to do it.

My coils have an extreme amount of silicone on it. What is the best way to remove the silicone? I assume I have to actually remove the coils? Is the silicone a special product for circuit boards?

Christioph, I’m not sure which part you’re referring to. Is it a component on this board? I googled 1084CM and found this part. I’ve seen that kind of heat print before, and it doesn’t necessarily mean that the part has overheated.

If your monitor turns on for a few seconds and then the backlight goes off, I would try looking for a cold solder connection first.

I don’t know if you’ve read all the comments, but there seem to be various components that have failed.

I was happy to find this blog in dealing with my Hp monitor. I am still getting to know the problem and the suggested solutions.

I did found an interesting thing as I was getting into the monitor and to the inverter board. There was a very dark (soot?) spot on the metal chassi behind the inverter board just close to a mounted part on the inverter board which says on it:

AIC
1084CM
387BB

It looked to me as if this part had overheated and thus made a heat print on the metal behind it. I was able to wipe it away with my finger.

Can you tell me what this part is and where to get it? It is a plastic brown flat box shaped part near the edge of the board where it connects to the main monitor card.

God bless the internet! Many thanks for the info in you blog. I followed the steps in the procedure and my f1703 monitor was working again in about 30 minutes.
The f1703 that I have now is replacement given under HP’s warranty, the problem with the original was exactly the same that the replacement one had.
The manufacture date of the one that I have just repaired is September 2003 and is a “reconditioned” unit. When I took the front off I found that half of the display fixing screws were missing, 6 out of 12. when I got the inverter board off and looked the solder side I found that all 8 connection points of the coils had been re-soldered in probably the worst work I seen on a circuit board in many years, all 8 needed to be redone. It doesn’t much good about HP’s repair department.
Many thanks for saving me many UK £’s
Steve Lee

To open the AOC LM729, what you need to do is pop off the silver front outer lining. It is held in by clips along all sides.

1. Remove the outer lining of the front using a small flat screwdriver, going from the top, then sides, and then finally bottom. Doing it in this order will make it easier to remove the bottom, as the bottom side is underneath the built-in speakers.

2. Screw out and remove the built in speakers. The speakers are attached using a grey cable, with the same dimensions of an IDE or Floppy cable. 4 Strands.

3. Remove the stand from the monitor. You may even want to do this first (which I did). All it takes is a small, flat screwdriver, and a phillips screwdriver. Pop out the cover right where the stand/swivel arm is, and you’ll see four screws. Just remove them and your stand is off.

4. Next, remove the screws holding in the display. There were 7 of them on mine. 4 at the bottom, 3 at the top.

5. After removing the screws, the screen is held in only by clips at the sides. Just pry the plastic away on either side, and you’ll have the screen out.

After you’ve gotten it out, you can basically follow the instructions here to finding your problem. On mine, I noticed a swollen capacitor. Going in the town now to get it replaced.

I too was jealous of the FiOS service, seemed like such a long wait. Download @ 15511kbps upload @ 1818kbps as tested on speedmatters.org. FiOS HDTV is also great. Sure hope you can get it soon! Thanks again for the fix.

Thank You Leslie Wong, Thank You, Thank You!! Had my youngest sister (hey she is only 51) re-solder my f1703. It has been up for 3+ hours instead of the -3 seconds it was doing. I loved not spending any $$$ for a new monitor, plus my sister & I had fun doing it. Even my 90 year old mom got a kick out of us fixing it!

Many thanks for this most helpful blog. Looks like this problem is more common than HP would have us believe! As per Shannon’s note, I too couldn’t see anything obvious, so I also re-soldered all four coils and guess what…my F1703 works like new too!

Gromit 588’s post
I,ve had my F1703 TFT for 14 months and ges whats happened, yes its blacked out. After extensive and expensive calls to the HP ‘helpdesk’ – only to discover that after one year HP want nothing more to do with you. I took things into my own hands. ONLY PROCEED TO FOLLOW THESE INSTRUCTIONS AFTER THE ONE YEAR WARRANTY IS UP AND YOU ARE READY TO TRASH YOUR TFT!
Tools you’l need a small/medium philips (star) screwdriver, a small flat head screwdriver and a knive.
1. Remove all electrical connections from your TFT.
2. Using the flat head screwdriver, remove the two blue plugs just above the silver stand bracket on the rear of the screen. Remove the two brass screws
3. The screen and the stand should now be seperated.
4. Using the flat head screwdriver gently prize the silver facia away from the blue body of the TFT from the outer edge – Best place to start is at the bottom corner of the screen near the menu – + select buttons. You will hear cracking – crack is good, snap is bad.
5. When the silver facia is removed, you will see about 12 screws on the front of the screen (these hold the screen to the body) – remove these screws.
6. Carefully turn the screen face down. You will see an aluminum looking heat shield. Using the knife cut threw the metal seal.
6a. Remove the two locking nuts in the blue 15 pin D connector.
6b. Remove the two screws on each side of the heat shield.
6c Gently push the heat shield towards the bottom of the screen.
7. Now reassemble the monitor using steps 5, 4, 3, 2 and 1.

I just fixed my friends F1703. Amazing that this was such a massive problem. I just melted the solder points on the bottom of the board and applied a little bit of new solder to the 4 (circular copper rounded) Toroids and it fixed the prob. I need to get a smaller tip for my soldering iron though because the points are very close to each other.

Your recipe of resoldering did the magic for me too. The PC board looked flawless, even with magnification.
I like to troubleshoot and would never have guessed, that bad soldering would cause such blackout problem 1sec after system powered on repeatedly. I am still at a loss, what shuts it down exactly at the same moment.
But I am glad the monitor works again thanks to your website.

Thanks for the info, I found 3 bad solder joints. I re soldered them and I have never had a problem since. I also have a hp pavilion a622n that was not working I checked the motherboard and it had the same problem. soldered 2 joints on it and now the computer works again.

Nothing comes up, it’s just that when I plug in the a/c adapter, the LED on the adapter blinks and you can hear it click. But when I plug one end to the wall and I leave the other end out, the light stays solid. I haven’t tested the voltage yet though, but will do soon enough.

I think the three lines should not be connected to the connector in the middle. IIRC, as I no longer have an f1703, that connector was just not making contact to the pad, so I just heated so it would only make contact with its own pad.

Thanks a ton! A friend’s F1703 had the same problem — blank, but turning on for a second then off on poweron. I found a cold solder joint on one of the leads on one of the toriod inductors and soldered it up and so far (after 15 minutes) it seems to be working great, thank the Lord!

If you mean an AC adapter, I’d try eBay. It doesn’t have to be specifically for a VX910. You just want the correct output voltage, at least the same number of amps (or more) and the right plug that goes into the monitor.

If you mean the power supply board thats on the left of the picture, then you’d have to find another broken VX910. eBay or Craigslist.

I’m impressed.
However, my problem is slightly different. I have a HP2025 monitor which is 2.5 years old but will no longer work properly as it refuses to ‘sync’ with any signal??? Any ideas? It’s in otherwise Ex condition.
Cheers Pee

Thank you! Thank you! Thank you! To anyone else who is experiencing problems with their HP F1703 monitor, try fixing it as described in this blog. It really worked! My husband had it fixed in less than an hour. Don’t be intimidated to try this. We know very little about electronics and were still able to fix this problem. We felt all was lost after a long conversation with HP customer service. The “supervisor” of HP monitors, as he described himself, told me that he had never heard of any issues with the f1703 monitor. He then went on to say that we should be grateful our monitor held out as long as it did! Shame on HP! Thanks to this website, we saved some money! Thanks again!

I could not see anything with my eyes…. However, with all the information about this problem and the coils, I figured why not re-solder all the coils. Works like new!!!! I spent maybe an hour researching the problem on the web, then I found this blog… It confirmed what needed to be done. Within an hour of reading I had disassembled repaired and reassembled the monitor! Thanks for your research(site authors, et al.) and help!

I have an HP F1503 monitor that was showing all the same symptoms as the F1703. On opening the unit up, the inverter PCB appears to be of a much higher build quality than that used in the F1703, but I did try resoldering all the joints on the main components (txfmr, inductors, caps, a few of the key switching transistors, etc) but this didn’t fix the problem.

Having read somewhere else that the AC Adaptors can also be a cause of this problem, I rigged my monitor up to by bench supply and “viola” – she’s working a treat! I can get a new AC Adaptor off eBay for < $30

So, if the resoldering job doesn’t fix your problem, take a look at the AC Adaptor. Mine was making a high pitched squealing noise (you have to put it up to your ear) the moment the backlighting kicked in and the monitor started to draw any significant current. I just assume the SMPS inside was going into current limit for whatever reason.

All of the solder joints for the inductive devices looked fine to the naked eye. However, I resoldered 16 pins (4 for each of the 2 yellow-body inductors, and 2 for each for the 4 large copper-coiled inductors). Put everything back together and … wow!! … the display lights up fine now. Thanks to all who have contributed to this site. Saved me $$$.

Dennis (Post 178):
How do you open the case of AOC LM729 ? There are no screws, no clips, just a tiny hole with a lock symbol.
Did you replace any capacitors or just fix the bad solder joints in LM729.
Thanks in advance.

To mr.leslie.wong. I would appreciate if you forward my message to Dennis.

Thanks a lot!!!
You helped me fix it, when i took it to the shop, they told me that it will cost me $300 and up to fix it. So i decided to buy new boards for the LCD, but when i started serching where i could get them i got to your site. your site was very helpful. THANKS.

I was wondering if anyone could help with this problem:
I picked up an f1703 for parts/repair that as being thrown out figuring I could fix it somehow. The LCD calls for 12V at 3.5A so I am using a 12V 4A max supply. I’m trying to use this as an external display for my IBM T40 laptop, but the all that shows up is a blank white screen. I installed the drivers for it and tried multiple display settings but theres still only a blank white screen. The driver installation detected the monitor but still nothing. I tried resoldering all of the major joints discussed in this blog, but no success there either. When there is power to the monitor and a signal from the laptop, the screen is white and the power button glows blue, and when the signal cable is unplugged , the screen goes black and the power button glows yellow. Ive tried this monitor on multiple computers as well. If theres any hope of salvaging this monitor, and helpful input would be much appreciated.
Thanks, Jeff

I’m afraid I just blew up my inverter board. There were no obvious “cold” joints (in fact, everything looked quite well put together), so I just re-soldered them all (took about an hour). When that didn’t work, I soldered together anything that looked like they might belong together.

When I next plugged the monitor in, there was a bright spark and my house was plunged into darkness.
Does anyone have any idea where one might find an inverter board for the HP 1702? It’s quite visibly destroyed beyond reasonable repair.
One would have thought it easy, but google is not its usual helpful self.

My hp f1703 had similar problem. The monitor will black out and I had to squeeze it, move it up and down and then it start giving blue lines. This was fixing the problem until the next start .However it was happening more and more often.
This is how I solve the problem
I fallowed the instruction to open it. It is important to know that you have to pray out the back cover .It is dark blue in my case. The front gray trim stays. I used a paint scraper it is durable and gave me a good leverage. I broke one clip only.
I opened up the metal cover (a few screws) and looked at the printed surcuits.Nothing visual. Then I connected it to the power and the computer and start touching elements on the circuit by hand. Every time I touched the processor (the big square black element) it affected the display. So I took that printed circuit off (4 screws and 4 connectors)
A good friend of mine works at a place where they deal with printed surcuits.He repair it by resoldering the processor. Do not try this at home .He uses a special gel and mini hot air gun to do that. He also applies a special heat resistant tape on the processor to protect it.
We had some beer and good chat.
It works well now
Good luck.

I just got a f1703 given to me at a garage sale. It has the black-out problem and the owner said he was told it was unfixable. I took it to a repair shop and was told the same thing. I was about to sell it for parts on eBay when I discovered this thread. I am happy to say that I simply re-soldered the coils and the monitor is working perfectly!
Thanks for the help,
David

Thanks for the posting of your solution. I have the same type of problem, but in my case, my monitor’s power led flashes twice when I turn it on before powering off completely. Therefore it is getting a signal but I cannot see any bad solder joints on the circuit board. I am curious if the chip in the lower left portion of the third picture you have posted has all three leads connected to the board or, as in my case the middle lead is not connected? This might be my problem with a melted lead or bad solder.

I had the same problem with my 17 inch HP 1702 monitor, the sceen used to black out a few minutes after powering on.I opened up the monitor (this was the most difficult part due to all the plastic holds). I found some dry solder on the coils/inductors and resoldered them. The monotor was working again. I think that the 1702 suffers from bad quality solder job. Thanks to all your post did not have to spend time troubleshooting this problem.

I have a HP1702 LCD monitor. The power failed – pressed the ‘on’ button and the green ‘on’ light flicked on for a second and went off, the screen didn’t come on at all.

After searching for a solution on the web, I came across this site. Brilliant!!! I had read enough to want to open it up and have a good look at the power supply circuit board.

Checked for dry solder joints, all seemed ok. Then on closer inspection, I found 3 capacitors blown (split and leaking). C818, C813,and C810 all 1000uF 16v. Relaced all with 1000uF 25v capacitors. Powered up the monitor and it works fine.

Re My HP f1703, made Nov 2003
Hi, Just want to say lots of thanks for this site. With the help of the information about cold solders and how to localise them contra blackouts, I could find the cold solder on the backlight inverter board and see myself the problem and have it fixt for a buck. One of the solders had overheated and disconnected. This is not my area at all, so it was so great to manage this by a website. Thanks again. John Martinez ,Sweden

I have a sony sdm-hs73. When I power it on it briefly display sometimes for 2 minutes or 5 minutes. It then goes black with the power led light on still . When i take it off and repower the same thing happens. I opened it and redo the cold solder joints on the power inverter board and it remains the same. Any advice?

What a winner!! Just tried the recommended coil resoldering, following a blackout problem with my 3+ year old HP Pavillion f1703 monitor and seems to have done the trick. Having spent 5 years in a repair centre – I can envisage what the problem is here. As it took quiet a “Beefy” soldering iron to heat up the coil pin – it would suggest a manufacturing problem with the production line. ie:- Not enough heat to wet the joint fully.

Hi,
As above mention I already resolder the 4 coils it works
fine for a few days. Now the problem is when I turn on the computer or I play some games, the sreen blanking 5-10 min then on again, sometime even longer time. I just wonder if I change the power supply to 15V 2A(I find it someone mention in forum) will it help? or any further solutions? Hope someone can give me a reply.

in my case mine was bubble soldering(soldering inside was empty)
look shiny but it was not enough soldering.
2of4 were shrunk when I used soldering iron.
Looking good but poor soldering.
I don’t know others

Harlan (or Gametec) recommends “take a small propane torch and heat the entire boards solder connections.” For readers of these posts who do not have much experience with soldering, desoldering, or other repairs, my advice is: do NOT try the propane torch trick! Leslie’s original post describing the use of a soldering iron, joint by joint, may seem painstaking but it is much safer. These circuit boards have some components that are very sensitive to overheating, and the propane torch risks destroying them (even though they still look OK). You can kill a fly with an atom bomb, but you risk a lot of collateral damage…

Play it safe, just use a soldering iron – it worked for me (see my post of March 14, 2007, above).

Thank you so much! A while ago my dad’s monitor stopped working (with the same symptoms) and when we tried to have it replaced under the recall we discovered that it’s serial was just after the recall series. I’ve had it in my room and it’s been working on and off. I had also noticed the faint image on the screen and assumed that something was over heating and turning off. It was not until last night (when I decided that it would no longer work) that I opened it up. I was planning on trying to find a new inverter, but ebay was lacking. Then, i found this post. upon inspection of the board i found a broken solder point which i assume is the culprit. Even if it’s not, thanks anyways.

Very Nice Post. good to see people trying
to help others. I would also like to add for
the emachine and other inverter boards
this is very common problem. and can be very
hard to find the cold solder joint with newer
surface mounts and small components.

Here is a tip if you have one you can’t find
with soldering iron. Take a small propane torch
and heat the entire boards solder connections.

I got a Tatung L71 from the electronic recycling dump, minus the power supply pack. A web search said it was a “debranded” HP F1703. Not wanting to buy a power supply in case the monitor didn’t work, I got an old 300Watt PC power supply, jumpered the start switch, and made a patch cord to go from the power supply 12 volt plug to the monitor. I started it up and it WORKED!!! (for about 3 seconds Another search on the web brought me to your site. I followed the stories and re-soldered all four of the torroids, and YES it’s been working great ever since. Thank you, leslie.wong, Thank you, I am going to give the monitor to my son for his birthday!

Never buy HP again… thats the lesson learnt… the worksmanship on the inverter board was soooooo shotty…. showed a former quality control guy and he was shocked it passed….

anyway- buy LG from now on for those of you who come accross this page – they give a 3 year warranty that is a swap– they just give you a brand new replacement if anything goes wrong…. something i will consider in the near future as I am looking for a new monitor due to the incompetance of HP lol…

Thanks for all the work you put in this Leslie–> two thumbs up to your sincere care put forth (HP could learn a lot from you)

Spend 2 days fighting with HP- Did a google and found your blog- opened up my 1703 and spent maybe 45 minutes from start to finish. Resoldered the four coils (8 places) put it back together and…………IT WORKSSSSSS!!!! EMAILED hp AND TOLD THEM THEY WILL NEVER SEE A WARRENTY CARD FROM ME BECAUSE i WILL NOT BUY JACK CHIT FROM THEM

Iif your monitor has a HD15F connector on it (the blue connector in the first photo labeled display), all you need is a new cable. It is not a special HP cable, your local Computer Shop should have one.

The monitor cable is just a standard cable with a HD15M connector at one end and a HD15M connector at the other end.

If your monitor doesn’t have a HD15F connector and the cable goes directly into the case, then you have a more complicated problem. You will have to disassemble the display and use a vga pinout diagram and solder each wire.

i have thsame montor as previously mentioned on this site. the vga connector on the cable has ecome extremely damaged, giving the following colours as a screen picture: red, or black. when it is red, you can see the desktop, but everything is red.in a desparate attempt i cut the cable, and attempted to attach another VGA cable to the previous supplied cable. unfortunatly the two cables are not the same, meaning i have many cbles that cam match the other ones, but then many wires that can go nowhere. has anyone got any ideas how to rewire it. And it being HP they dont sell the spare cable that you can yiust attach the the points in the monitor casing. Really need help!

Thanks a lot for this web page, it helped me fix a dead f1703. I checked all the solder joints mentioned above, they seemed fine but I decided to remelt them anyway and that did the trick. Thanks! I love the Internet!

Mr. Wong,
I really appreciate you keeping this instruction posted. I resoldered exact the same spot as you pointed and fix it greatly. It’s easy to buy new one, but more than happy to recycle it. You’re saving a planet!

I followed your directions and also the link to gromit588/syben’s detailed instructions on disassembly. The board was full of shoddy solder joints. I reworked them all and the monitor is now fully functional.

Dear Leslie-
Thanks very much for this web site. I just bought an HP 1703 for under $20 USD from someone who I told about this, but said they would never attempt the repair. Well, I did it and I am now looking at a working monitor as I type this.

For those considering this work: This monitor did not show any sign of life when connected to a working power supply – just a dead screen and even the power switch did not light up. When I took the monitor apart I did not see any cold solder joints on the backlight inverter board. I reasoned that if Martin Forsburg’s post (above) is right, any component attached to the board with silicone cement before soldering might have had problems – so I simply resoldered each terminal for the four inductors, the power connector, and the sound connector (the sound connector probably didn’t matter). Seems to have done the job!

Look at my comment from November 28, 2006. There is a link from archive.org to the original US HP Support document that offered an extended warranty. That document no longer shows up at the US HP site.

Try checking with HP Support in your country. If you argue firmly but politely, you may have some success (someone else mentioned this in the comments). I think it is highly unlikely that you would be able to have HP repair your f1703 under any warranty at this point since the manufacture date on the warrantied f1703 was 2003.

Like various other readers of your blog entry, I faced the same problem with HP F1703 monitor and opened up the monitor using the disassembly instructions from gromit588. I was not able to locate cold solder joints (all solder joints looked shiny) so I just heated up several joints, particularly the ones under the 4 coils, the two power connectors, and a few under the plastic cover on the side that connects to the display board. I did find a glob of loose solder lying on the component side of the board, but couldn’t trace its original location.

The monitor is now working! Thank you very much to you and other readers!

I own an HP vf17 flat panel monitor and the screen goes white (not black). I know it’s a problem with the monitor and I’ve tried everything mentioned in all the blog comments with the exception of taking it apart. Do you think I have the same problem as those with the black screens ?

Have you tried the f1703 on another computer? Are the display sync settings correct? Try 60 Hz. Native resolution for this display is 1280×1024.

If it was working correctly when you obtained it, poor solder joints (use a 10x magnifier to inspect the solder connections) could also be the problem, though I have heard few complaints about sync problems.

If the f1703 does not work on another computer, you might try taking it a apart and looking for leaking capacitors (search Google or this page) or other components. See Martin Remmers comment on this page. He had to replace some transistors.

I used a 10x magnifier and the cracks in the solder were very visible.

You can use a DMM and check for continuity from the component side to a trace further down the line that should be connected. You can see the globs of excess glue that were used on some components before soldering. Those are the connections that I would check first.

I’m a tech at a computer shop i bought two busted monitors for 15 each with this problem one being a f1703 and another is a 15 inch mag product number lt575s with almost i dentical problem i havent gotten around to fixing them yet as i was researching tonight and found your awesome sight i was wondering will al the soldering joints on this looking fine do you still think thats the most likely problem? im fairly certain its not the psu so i guess thats all it leaves right? thanks for these great post and take care.

Had started to shop around for a replacement monitor but thought I’d Google before I bought one and found your posting. I did exactly as you described and now have one fully functioning F1703 – many thanks for saving me £100s!!

I am new to this. I was able to take my f1703 apart. Problem is I have no idea what a ‘solder joint’ is to look like, hot or cold! The pix don’t really give an iead. Am I supposed to looking at the metal tips coming from board?

Another satified customer. My F1703 was sitting in a corner colleting dust for the past 6 months before I found this site. Within a couple of hours I had it back up and running. While I had it open, I went ahead and re-soldered all 8 of the inductor terminals and the 3 power connector terminals. It did the trick. Thanks!

Its possible that theres something wrong with the power supply. You can also try another ps if you can find one that has the correct voltage and at a minimum, the same or more amps.

The only way to be sure is to measure the output with a multimeter. StreetTech.com has a guide to digital multimeters. If you dont have one, they have some inexpensive meters at Radio Shack. Fluke makes some of the best digital multimeters. Many professionals use them.

You can try wiggling the plug where it connects to the monitor while looking at the LED indicator to see if it flashes because of a loose connection between the power jack and the PC board its mounted on.

I assume you looked at the Dell troubleshooting page. If the ps is OK, then you have to decide if you want to tackle fixing the display yourself.

I have a Dell 1800FP and it is dead, no led lights, so I thought it might of been the power supply, but there is current coming out of the power supply. Ca a power supply be defective even though there is current coming out? With these symptoms what else can be a cause? Faulty led switch panel? Thanks for you feedback.

My XGEN 19″ LCD is now displaying a split in half image each side has a scrambled image wave horizontal lines on the complete screen. I hear a small buzzing sound from inside the case. I will need to reopen my case to check where the sound is coming from. I did check the back light the first time I opened the case and they were working, so I know it should not be that. What would cause an image to scramble like that, bad controller board? I also notice that there was a board other than the controller that is built into the lcd monitor, it has where the internal video wire connects to the controller board, what normally is this board on the lcd? Thanks, sorry for so many questions.

If you shine a desk lamp on the dark side, can you see the image from the light side continuing over to the dark side, or is it completely black?

If you can see a faint image on the dark side, it sounds like one of the backlights is not working. It could be the inverter or the bulb itself.

I don’t take any responsibility for this, but if you know what you are doing, you can power it up when you have the case off and see if the backlight is working on the dark side.

I don’t know how the X2Gen is built, but you could try swapping the working lamp with the one that doesn’t work, if you find that is the problem. For some theory and a fix see this post: Instructables. leevonk uses CCFT lamps + inverter (similar to the type that case modders use) to repair a non-working backlight.

I have a 19″ X2GEN lcd that only display half a screen of image, the left side is black and the right side has a perfect image (so the image is cut in half not shrunken). What do you think might be causing this problem? I tried taking apart the lcd and reconnecting the insides: inverter, logic board, internal video wire. Before all this happened, It did work for 2 days when I first connected this LCD, then it started to get a little static on the left side and eventually no image on the left, only on the right.

Your suggestions, or anyone who might have an idea where to start with this repair is most appreciated ! Thanks!

Thanks for the info – it solved my f1703 problem – it displayed the screen for 2 seconds everytime you turned it on, then went black. My cold joint was just 1/4 inch from your circled solder joint. Now it is up and running full time!

Hi there.
I have an HP L1502, and i’ve fixed it with the help of this blog. When inspecting the soldering joints I noticed some of the capacitors were not flat at the top, a little bumby, not misscolored. I remember i’ve got an old powersupply, took it apart and found 4 capacitors that i needed. Desolder them and solder them on to the monitorcard. And now the monitor works again.

If your monitor is something like a E17T4, it should work with any computer that has Analog (VGA), 15-pin mini d-sub VGA connector.

If you’re saying that the screen doesn’t come on, I can’t really help you. You have to have some knowledge and experience to take it apart. If you could explain your situation a little more clearly, maybe I can help.

If your keyboard is broken and you have to write in all caps, you should get a new keyboard.

However, HP Hong Kong denied ALL problems for this monitors. They said they could help only if I could find a similar link on their site. Well, all related links has been removed.

So, it leaves me no choice that I have tried to fix it myself. However, seems the problem is the same as J. McGinnis, one C5706 was fried BADLY. Even the PCB board was fried to crack… I can tell that even a replacement of the transitor can’t be done.

Anyway, to avoid a fried transitor to fire my home, I am going to sold the monitor as bad parts.

Anyway, your diagram and the gromit588s post about disassembly is really helpful.

My HP 1703 went black and the power button would flash on and off. After rebooting I would see a faint image and same thing. The power adapter light would also flash on and off. I thought the power light should stay on and was defective. This one had an output of 12V 4.16Amps. I found one with 12V and 5Amp output. When I tried it the screen image came on momentary much brighter and then went off. The power light on the monitor stayed on. Then smoke started coming out the top. I was told that the old power adapter had a short circuit detector–that’s the reason for power light going on and off. My new adaptor does not have a power light or short circuit detector, so when I turned it on the monitor light stayed on and fryed some parts. I guess it made it easier to find the defect. Now I find two fryed transistor next to the lower coil in your diagram. The have C5706 J3 on them. I found replacement # BJC5706J3 and will try to replace them and see if it works.

Thank-U so much mr.leslie.wong! I did exactly as you stated to my HP f 1503 and guess what? Thanks to all your great info it now works again!
OML Your Great!
Thank-U…Thank-U…Thank-U mr.leslie.wong From Pam in Canada

Hey Leslie- your advice worked like a charm. I have the 1703 and experienced blackouts like everyone else. I called HP but said they stopped exhanging defective monitors for new ones at the end of last year and could not help me at all. I decided to take matters into my own hands and ripped open the monitor only to find a bad solder joint which connected one of the coils. I re-soldered the joint and my monitor has been working fine ever since! Thanks again for your great help- Torrey Hecht.

It sounds like the backlight isn’t working. I googled: Acer AL1713 backlight – and found an AL1713 on eBay that had a similar problem to yours.

You could sort of hit the side of the display sharply and see if the backlight flashes on for a second. That would indicate a loose connection.

If you’re so inclined, you can take it apart and look for cold solder joints. I recommend that you use a 10x loupe. If you don’t know what to look for, google: cold solder joint – and look at the examples.

I have a blog entry that refers to an Instructables.com article on replacing a backlight. I also have a blog entry that has a link to a soldering tutorial.

HI , Great Info in these post. By the sounds of it My Backlight may be the problem? I have a Acer al 1713 flatpannel and was working great til all of a sudden most of the screen went dark, Not completly for I am able to see if I am close to the monitor. It’s like my monitor only has 20 % lighting.Every now and then the lighting do increase to probably 60% but is constantly pulsating or flickering state of 20 % lighting.At time the upper most left corner is lighted up but I can not see the GREEN Start button on the lower left hand corner. My best description is put On a Weilding mask or Dark sunglasses and you have my monitor to what I see. (Forgive me But I am trying to word this in the most correct way). I am actually using this monitor now as I type this (hence any typos, hard to see LOL ) IS this a Backlighting problem ? Or something else all together ?

Thank you, Mr. Wong. The coil pins on my F1703 looked well soldered but after heating them up and applying a little of my own solder to them, it works. I spent hours searching online with no luck until I ran across your site. You are the man!!

Craig, I have the f1503, the board does look a lot different, but if you get a magnifying glass and inspect the solder joints, you may be able to see incomplete solders – mine actually looked like donuts – no solder at all in the middle. If you just go over any you find, you’ll probably solve the problem – it did for me. This was the first time I even touched a soldering iron, so I was not very confident – but I’m glad I did it!

I’ve never seen an f1503. If you search this page for f1503, you’ll see some owners were able to repair their displays even though their f1503 is different from the f1703.

If you have the circuit boards removed, the best thing you can do is to look at each solder joint with at least an 8x magnifier. Google: cold joint solder – and you can look at pictures of cold joints so you know what to look for.

If your display works then the backlight goes off, then it is a loose connection.

wow – thanks so much for the info. I have an HPf1503 that had the same problem. Although my board looked a little different, the pics were still very helpful. Under a magnifying glass, I could see several solder points that were incomplete. I put beads on the conspicous solder points and TA DA – a working monitor. Thanks tons! You saved me a couple hundred bucks!

Leslie, I found your posting very helpful, i too re-soldered all four coil packs and fixed the thermal problem, it does help to have an electronic background, but i believe anyone who can turn a screwdriver might as well try if nothing to lose! Thank you much……Gary

Leslie: Thanks. It’s been 55 years since I learned to solder in an Electronic Engineering lab in college. I’ve done little board work since. But I took a leap of faith and even with my old old eys and my slightly palsied hands I fixed it. Took 40 minutes from disconnect to fix and turn-on but, WALLA it works. Too bad HP couldn’t at lease offer a similar kind of help. From junk to a working monitor and a smile on my face, I thank you again.

Thanks for this excellent blog. I myself found out about this issue when working as technical support for a local school. A member of staff brought their f1703 in from home claiming it as “dead”. It exhibited the same symptoms as the recall, and fit the criteria. After a call to HP, a new one arrived. That died in the same fashion, so we called again and got another new one. We called yet again, this time we got a brand new 19″. We’re still using it in the workshop.

I tried the same trick with a f1703 I bought from eBay, and lo and behold, HP replaced it and I’m now running it as my main monitor and my brand new Hyundai B71A as a secondary.

I’m now trying to get hold of another f1703 so I can call HP and get a new one. I’m pretty sure that the HP “technicians” know nothing about the recall, so if you argue with them for long enough you can get a new TFT out of them, regardless of whether the TFT is actually yours or not, and regardless of the expiry date on the recall.

Thank you very much for your advise! I resoldered the connections of the four coils and the connections of the power jacks without even using extra alloy! I bought the (defect) display for  10 (about $ 14) and with an hours work, my girlfriend can enjoy here own PC and TFT and leave me with my own PC’s!

I just wanted to thank you for the unmeasurable help that this website provided by giving the how-to-repair the hp f1703 or f1503 lcd monitor. I was about to throw away my f1503 and had already begun a search for a replacement. by following the easy to follow directions. I have now a refurbished monitor.

Has anyone had a problem with the f1703 going black and changing the resolution settings every 20 -30 seconds? I reset to 1280 x 1024 pixels and it goes black and jumps back to 800 x 600 pixels. Any help would be appreciated. Best Buy is trying to tell me I “might” have a virus. (I don’t believe it.) I have extended warraunty.

You still might be able to repair your f1503. If the display sitll has the same symptoms, you just haven’t found the bad connection. Try looking at each solder point with an 8x or 10x magnifier and you may be able to find the problem.

I attempted to fix my f1503 by heating up the joints for the 3 coils on the inverter board, but unfortunately I still get the same symptoms ( power-on, 2 seconds of dim red then blackout). I’m not an experienced solder-er, so I’m at least pleased that I didn’t cause more damage.

Call HP about the problem, It is a pain, but once you talk to a case manager, they will send you a new 19 inch monitor, not the 17 inch!!! The recall ended in september, but if you hassle them enough, they will send it to you. I am happily using my new 19 inch right now!!!

Mr Leslie Wong.
My H.P flat screen model pe1229 model namef1703. Out of warrantee. push on of button to turn on screen cucles on off on off continuesly. How do I dismantle monitor rom caseing. Can you give me direction I think I have an idea how to. but I want to be sure. thank you

Mr. Wong,
Your website has been very helpful. I too have experienced the same blackout issue with my f1703 monitor after approximately 29 months of use. My dealings with HP have been extraordinarily frustrating, especially in regards to the extended warranty that was granted previously. Can you (or any of the individuals posting) post a PDF, screen shot, or copy/paste the language that was posted in the extended warranty on the HP website? The links to the HP website listed at the top of the page (as well as the CNET portal) no longer bring up the warranty.

Again, many thanks for your efforts in assisting others with this aggravating issue.

This is a link to the UK HP Out of Warranty Exchange & Repair Program. HP wants 93 GBP excluding VAT for a repair/exhange. Usually, the warranty on the repair is 90 days. There’s also a link on that page for Terms & Conditions of Repair/Exchange Units and a phone number at the bottom.

Hi
Has anyone had this problem. I had the original faulty monitor, had it replaced free of charge under the extended warranty. The replacement has lasted all of six months and is displaying the same problems as the original, screen going black etc. Is there any hope of trying to get the replacement replaced. Also does anyone know the phone number to ring in the UK as I can’t seem to find it anymore.

I checked some of the US computer parts sources for repair parts and couldn’t find anything for the F1723.

I did find an EU HP parts distributor, ICS Europe. If you use the keyword “inverter” to search you can find 2207 matches. Unfortunately, their search engine only accepts a single keyword, e.g. “Hewlett” gives you 1661 matches. Even if you are able to email or talk to them and find the right part, the cost of it will likely be more than it’s worth.

It may be easier just to buy a new display. For example, this vendor, Newegg.com in the US, (that I buy stuff from) lists 97 17 inch LCD monitors starting at US$147, about 114 EUR.

I don’t know if you have read most of the comments, but the problem might not be detectable unless you use large magnification (I used a 10x loupe) or a VOM.

Hi,
I have a f1723 and its got the same problem as I’ve read here blackout of whiteout rather after a few minutes…it got gradually worse over a few days. I’ve got the back off the monitor and can’t seem to see any bad solders and the heatsink is screwed onto the power board so I don’t think I move it further down….although all the instructions I’ve found for fixing the f1703 don’t exactly apply as its different to take apart and doesn’t look the same as leslie wong’s pictures, does anyone know where you can get another board for the f1723.
Thanks

just had the same problem, but my screen was already repaired by HP service -the Netherlands, last june.
after 6 months we had the same problem again; out of warranty said HP. standard repair costs are 152,00 EURO.
I saw this morning your solution – and fixed it!
It works.

Thanks, Leslie for taking the time to write this. It was right on. I found a different cold solder joint under the magnifying glass. I removed the old solder and re-soldered that point and all worked like it should!

You didn’t say if you were able to adjust the screen image with the setup controls. You can try to see if that works without the monitor connected to a computer.

That bulging device is a aluminum radial lead capacitor, not a resistor. The voltage and the capacitance (uF) should be printed on the side. If you’re in the US you can probably get one at Radio Shack or online at Jameco or Digi-Key. If Radio Shack doesn’t have the exact one, get one with higher voltage but same capacitance.

Replacing the capacitor doesn’t guarantee it will fix it, but it seems to be the most obvious thing. If you get a replacement, remember it is polarized – it has a positive and negative side. The negative side is usually marked with a line down the side. Make sure the polarity is correct when you insert it into the circuit board.

You probably can’t do much more unless you have a schematic. If that doesn’t work, I’d probably start looking for a new monitor since they’re pretty cheap these days.

I also had problems with my F1703 Monitor.
Thanks to info listed here I was able to track down
my problem. In my case, two transistors, Q211 and Q212 were shorted (These are 2SC5706). When I replaced them with 2SC5707 (the same but slightly higer collecter current rating), those only lasted about two hours. That is when I read here about the excessive silicone problem. I got out my 17x loop, and checked the solder connections on the coils, they were fine. Then I checked other connections that had silicone above it, and sure enough, C214 had a cold joint. This cap is shown on your photo, it is blue, and just below and to the left of the bottom boxy transformer. You can see the liberal amount of silicone on yours too. I sucked out the solder from the joint, and re-soldered, re-replaced Q211 and Q212, and it has worked fine ever since. With this joint open, it probably oscillated at a much too high frequency, or had excessive ringing, burning up one of the transistors first, which then killed the other one. By the way, I got the 2SC5707s from I place called B&D enterprises, in Philladelphia (800)458-6053. They were 4.23 each.

I tried the monitor in different computers, and it doesn’t work on none of them. I checked the fuse, its good, and the bulgy resistor looked like it was about to leak, It had a stain on it. Do you think if the resistor is messed up, where can I buy new one? And do you think that would fix the problem? Or if you have any other ideas please let me know.

Can you display the setup controls to adjust the screen image? On page 7 of the VX710 User Guide, there are instructions for OSD and power lock settings. Do those do anything?

It also says if you drive the monitor at greater resolution than 1280×1024&75Hz you can permanently damage it. Did that happen?

I circled two things in your photo that you can check after disconnecting the power: The first thing is the fuse. It is inside the black shrink wrap by the AC power jack. You can use a sharp knife and cut the shrink wrap off and see if the fuse is blown. Or you can use a VOM meter to check continuity.

The other thing is that capacitor. It looks like the top is a little bulged compared to the other ones. Is there any brown color around the capacitor, like glue or paste? That could mean the capacitor is bad.

Hi
I have a viewsonic vx710 monitor and the power button is flashing. I tried different power supply and it didn’t help. I called viewsonic but they are asking for the receipt but I loss it so they do not want to help me. I open up the monitor and follow your instructions but i couln’t fix anything.

I have attach some pics of my monitor to see if you can find the problem

Since I am unable to properly solder anything myself, I decided it would be best to have a professional solder it. I took apart my defunct monitor and took out the power board and brought it to a local TV repair shop. I told the repair man exactly what to solder (the four coils) then the man wanted $20 to fix it, so I offered him $15 and we made a deal. I picked up the board the next day, inserted it back on the monitor and now it works perfect. We’ll see how long the repair lasts.

Hello Mr. Wong.
I am suffering from the same problem. My F1703 goes to black. I have read your solution and browsed the internet and I am sure the solution you serve is the right one. The problem is that my English is ok, but not good enough to handle the technical jargon. I mean that terms like bad solder joints or cold solder joints are not very clear to me. I don’t know exactly what to look for on my backlight inverter board.
I am Dutch and I am wondering if there is perhaps a dutch person on this messageboard that can help me or someone who can explain things to me more basically. The fact is, I am not very skilful with electrical repairs.

Your a genius. Took me half a day to track down what my monitors problem was. I took my monitor apart resoldered my connections and one other area that was obviously not right, and I’m back in business. Took maybe an hour all told. Thank you so much. HP tech was absolutely no help at all, but with your help this was a snap. Shannon

Do the tops of any of the capacitors look like they are bulging or swollen? The tops of the capacitors should be flat. If there is a short circuit, that could overheat the capacitor and short it. It might not necessarily be discolored.

Hi. I am struggling repairing a hp 1702 monitor.The backlight comes on for a second and then dies. One of the two back light connector does not operate.The supply to the circuit is 12v.Any schematics available ?. Thank you for helping.

To David A.
I recheck the benq power board last night and notice that there ‘s some slight discoloration near the top transformer which is responible for the top backlight(flip the circuit board upside down).

I guess the transistors and transformer get little too hot and cause some ptoblems.

Is your power board a Benq 48.L8502.
Let me know whether you have discoloration at there.

Does anyone know how to check whether the transfomer and transistor are faulty?

I heard that many dell bE172fpb with benq board have the same problem with the transfomer and trasnsitor.

I have a HP f1503 LCD, it goes black after 1 second and nothing is shown.

After i took it apart, I found out the board is completely different than what is posted on the site. The boards(power + signal processing) are made by Benq. And instead of having 2 cables connect to the LCD panel,the Benq has only one cable.
Also the whole board has no blue . I recheck the board again, and found no cold-solder joint,

We had 3 HP1702 monitors which had a similar blackout behaviour – no power at all.
By optical inspection of the integrated powersupply to eventually find some bad solder-joints like described above, i found 3 blown capacitors (100uF/16V) – after replacing them (precautionary with 100uF/35V) the monitors are back to life

I too have the HP 1703 and like the rest it failed a few weeks ago shutting off after about 1 second. I knew it was out of factory warranty and I used a backup monitor temporarily until I had time to find another monitor I liked. I loved the 1703 and P.O.ed that it failed so soon.

I stumbled across this site when I was looking for the specs of the 1703 so I could get a new monitor similar to what I had and was angered after reading about the defect. I figured whats to loose! I am skilled with a solder iron so I went for it.

I just wanted to let you all know that after getting to the power board it took a magnifying glass to spot my cold joint on the coil. Even though my 50+ year old hands were a little shakier with the iron than the last time I did a repair it worked perfectly.

Thank you so much. I didnt realize how much I liked the 1703 until I put the backup monitor on the computer.

I completely agree. I have an f1503 with matching serial batch indicators, construction timeframe and symptoms as described for the 1703.
Unfortunatly even with the extended 27 month warrenty, I’m about 2 whole months late, even though the monitor has only started presenting symptoms a few days ago.

I’m trying to work HP over to have them cover it anyway, since it is presenting symptoms identical to a known manufacturer’s defect for the same model of slightly larger size.

Mr. Wong,
Yes my 1503 does exactly what is being described with the 1703. Dim after a second or two. I’ll continue to look at the solders, may just reheat all to be sure. I like to fix things myself and really dislike new things to break down, especially right after warranty expires.
HP should cover 15″ monitors the same as the 17.” (extended warranty)

Leslie, I just wanted to drop a line letting you know I very much appreciate the information you provide on this page. I reheated each of the solder points on the inductors and my monitor is back to life. Saved me 200 bucks!

Does your 1503 backlight go off after a few seconds? And can you still see your desktop when you shine a bright light on the display from the front? You should be able to see your cursor move, for example, even with no backlight.

I used a 10x loupe to look at each pad where a component came through the circuit board. I don’t think a blanket statement can be made about a specific component always not being soldered correctly. Damo commented (08-14-06) that he found 25 bad joints.

Thanks for the posting of monitor repairs. Since my 6/1 message, I just now opened my 1503. Don’t see anything obvious. Reheated points of “coils” but no luck. Noticed a coment back in June stating to start with red coils. Any pics or details would be helpful. Thanks again

thanks for this information. My wifes 1703 started going black about a month ago…first every once in awhile, then it went out and would not come back on. I took the beast apart…I thought it wasn’t all that easy, really…touched up the power adapter, and the 4 coils…one of the coil connections was obviously not soldered well…the rest of the joints had big holes under the solder when it melted….so the connections were less then optimal.
Brought it home, plugged it all back in..and viola..it now works. We will see how long it stays on.
hopefully for quite awhile..save a couple of hundred dollars..thanks again.

great post, this is exactly the problem i just started having with my f1703, which is sadly outside the special hp 27 month extended warentee on this problem. looks like i need to do this myself. i’m comfortable soldering, but i dont see how to get the plastic cover off this thing to get to your first picture, any suggestions? thanks!

Thank you, Leslie. It does look pretty simple! But guess what? I found out that my extended warranty which expires THIS SATURDAY (8/18)(!) covers this monitor. When I initially called HP, the CSR told me that although the computer was covered, the monitor was not. He told me to buy a new one (HP, of course!).

But today I brought my service contract in to Best Buy (where I bought it) and they said it WAS covered (yea!). They are sending me out a “new” one (refurbished–I hope the tech that worked on it read your website first) at no charge! So I hope this solves my problem. But thank you so much again for your invaluable knowledge and kindness.

BTW, for all those still having problems, I also found some good information about this monitor on CNET Peripherals Forums (http://reviews.cnet.com/5208-7590-0.html?). I think that’s the right address–otherwise your readers might try to Google CNET Peripherals Forums. I think it was that site that lead me to you.

And I have this to add. When the Best Buy tech did a diagnostic on the monitor (over the phone) to see what was actually happening, she had me:

1. Turn off the computer
2. Restart it while continually hitting F5 (I think, or maybe it was F8) to get it to go to a SAFE MODE screen.
3. Select “Start Windows Normally”

At first, on the Safe Mode Screen, the picture was worse than it ever had been–the words were hardly readable at all. But I was able to do it and I got my picture back–better than ever (no horizontal lines at all, but still some slight flickering). Just thought I’d mention that this worked for me, though perhaps it is a temp. fix. Others on the website I mentioned did not have success with this approach. But if it works until the new one comes in the mail, I’ll be a happy camper.

I, too have had this problem–especially when I turn the computer off and on again. I contacted HP but was not within their time period for the replacement. However I found that if I fiddled with the power cord leading to the monitor–or disconnected and re-connect it again (sometimes after several tries) I could get a picture again, although the picture I have now is terrible (lines, slight flutters) and have difficult reading fine print (at least its working though!) I’m pretty handy but don’t have any experience with a soldering gun, and don’t own one. If I get one, should I get a cold soldering gun? Is it worth the investment (doubt that I’ll be using it again much). Also, do you have any suggestions as to who to take this to if I don’t want to do it–preferably someone “cheap” who could just do a quick solder if I’ve done all the pre-leg work of taking it apart and then putting it back together? Any info would be appreciated. So nice to know there are still giving people like you around. Thank you!

In the first section of this post and in Irma’s comment, there is a link to the f1703 problem at HP. At the bottom of that page, there is a Quick find your product where you can enter a product number. You may want to try to talk to HP Support or your vendor, because you have such a high failure rate in a batch of monitors. Besides that and searching the Internets, I can’t help you too much more.

My problem is with the 1702 hp monitor. My company orders 10 total and but 8 monitor total went out on us before the year was up. The 8th monitor just went out on us and the warranty is expired. Is there any suggestions or sites that I may find a recall on the monitor.
Thank you
Gwen

Have just received a new f1703 to replace a f1723 which went on the blink, after 16 months, under a PC World maintenance contract. It was built in China in 2003 according to label. It’s fine so far, but it looks like it might fail in about a year also as happened to many of you. Thanks for the info, forewarned is forearmed! Do you know if the f1723 has similar problems, or was I unlucky?

If you find a power supply that is more than 4.2 amps or 50 watts, that should be OK but be sure the output is 12 volts.

Maybe you can borrow the correct power supply from someone you know. If, with the correct power supply, the monitor doesnt work and you are apprehensive about taking it apart and soldering, you shouldnt have a problem selling it on Craigslist or eBay.

I don’t know if you can help me or not, but I figured it was worth a shot! I 2 have a f1703, mine was manufactured Sept. 2003. I bought it a few monthes ago from a friend and it didn’t come with any cords attached, so I bought the cord that goes from the monitor to the computer from Staples and figured I had the power cord at home to fit it. (I seem to have a really big collection of them for some odd reason) Anyway, hooked it up to the computer and tried several cords. With some of them the light would come on for a second then go out. Found one that powered it, and was fine for a week or two, then the picture started messing up, tried to fix that prob. with the on screen buttons, etc. I unplugged it, and saw that the power cord had been melting, (it was one with a box in between), I tried several, actually all the other power cords I had, and nothing, not even as before with the light coming on for a sec., and then no power. I have no knowledge with a soldering gun, or how to even do it. I also know after searching for days about this problem for a fix it yourself site that I shouldn’t have plugged in all those cords, because one of them could have had to much volt., etc. I looked for the correct power cord at Best Buy and they wanted like $85. I can’t afford to purchase it if I messed up something inside the monitor or something! Is there anything at all you can tell me about this prob.? I am sorry this is so long, but didn’t know how else to explain! You semmed to have helped alot of other people, hopefully you will have an answer or some advise for me!

Oh, one more thing. The power cord that did work, I didn’t even think to see what the volt, or anything else was before I trashed it

Just to clear up the air. Your power supply would not be causing the problem. Having more Amps is fine but if your device draws 2.5A and your PSU only is rated for 1.5A you will have a very short lived power supply, with excessive overheating. That is if the device works at all.

On to my second point. I bought my f1703 for $10 bucks at a used parts store. I knew it didn’t work but I thaught I could resell for parts on ebay and make some cash. Well, after I posted the item I got a message telling me about the recall. My monitor was included. HP agreed to replace the monitor even though I wasn’t the origional owner. They also sent me a 19″ as a replacement. The best part about this is that the base on my f1703 was so large that it wouldnt fit in their return box and then it was made better yet because they had no return label. I was told to junk the f1703 which thanks to this article. I have fixed it and have 2 monitors.

I guess I can’t complain but I do wonder why HP would allow me to keep the old one. I guess it don’t matter though!

I’m not sure about the power supply. It seems that it provides more than enough current. I think it would only draw the amount that it needs, as long as the output voltage is correct. Someone else can correct me if I’m wrong.

The other thing you can check: after it blacks out, try shining a bright light on the screen (like a desk lamp) and see if you can still see the desktop image. If you can your cursor moving around, for example, then it’s the backlight that’s not working.

It sounds like a similar condition as the HP monitors, if it’s out of warranty and you don’t want to spend the money to get it fixed, you could try to take it apart and look for cold solder joints.

Hi, I’m having troubles with my own monitor. It’s not a HP but a Gateway. What happens is after I turn on my monitor, after say 15 minutes it blacks out and I know theres still power because the LED light is still on. If I turn it off and on again, I can see something on the screen but after 2 seconds it turns back off. I also noticed that the screen stays on longer if I decrease the brightness.

Another possibility for my troubles however is I have the wrong power cord. The back of the monitor says I need a 1.2A but I have a 2.5A. It turns on and everything, I’m just wondering how much affect that would have.

Thank you for your informative web page. A f1503 was given to me by a friend after he had purchased a new monitor because of the f1503 continually flipping off. After a Google search I came across your site, and was able to easily dissect the f1503 (virtually identical to the f1703). Despite there being no visible cold solder joints, I resoldered the three (one less than the f1703) coil connections, and sure enough it works beautifully! Thanks again for your informative posting, and if any of your readers are having trouble with their f1503, first heat up the connections to the red coils. Thanks!

I don’t know if the construction is the same between the f1503 and the f1703. The CNET forum posts that I linked to in my post were the one’s that helped me take my monitor apart. When I started taking my monitor apart, there was no extended warranty, so there was nothing to lose. I just started unscrewing stuff and carefully prying apart things. If the idea of doing that doesn’t seem right for you, try getting a repair estimate. Unfortunately, with the price of monitors, it probably isn’t worth it.

My HP F1703 monitor ‘died’ after its manufacturing date passed the HP extended repair period – typical. Tried resoldering the 4 coils (solder points looked fine) on the inverter board as suggested but that didn’t fix the blackout problem. Then another poster mentioned that resoldering the power connector to the inverter board solved his problem. Again its 3 solder points looked fine, but I resoldered anyway and this has solved the problem !!! A variation on what’s mentioned here – therefore don’t give up if you don’t see any obvious bad solder joints and try resoldering other [good looking] solder points if you have no luck with the coil solution provided here.
Many thanks for pointing me in the right direction and saving me throwing away a fairly new monitor for the sake of a zero-cost repair.

Thank you for an informative, excellent post. Your English is also excellent.

On my circuit boards, I did not observe excess silicone coming through the mounting holes, though I did not look for that problem. I used a 10x loupe to check the solder joints where the pins from the components came out on the solder side. The loupe showed the obvious cause was a cold solder joint.

In my case, just heating the connection worked. I have seen video of circuit board manufacturing and IIRC, the circuit boards float over a “pool” of solder (wave soldering). Your post is an great explanation of the cause of the poor soldering.

I have some more information for you regarding this problem, maybe you can publish it on your blog.

The reason for these bad soldering points is that the silicone used to glue the components to the PCB has poured through the holes and made soldering almost impossible – and also destroys the solder since it melts and isolates the soldering point. This is the reason for the excess heat that is built up during use of this power board.

You will have to completely remove all four inductors (coils) and remove the silicone on the PCB and in the holes for the leads, otherwise the problem will probably come back soon. You will also have to clean the leads on the inductors (coils) with a sharp knife or something similar so that all excess silicone is removed before you resolder them – be careful so that you don’t cut the leads. After you have resoldered the inductors use silicone to fasten them to th PCB again, but be careful not to use any silicone on the leads that you soldered, just on the sides of the inductors where the silicone cannot pour into the holes in the PCB or make contact with the leads. You will need this silicone to fasten them with so that the inductors won’t fall of of the monitor is handled with too great force – possibly the inductors will make a bad noise also if they are not fastened to the PCB (they are mainly used for removing excess spikes on the voltage lines but they are used in a high frequence switching powersupply so they might “scream” if they are not properly mounted).

Also check all other hole mounted components for overheating due to excess electrical currents flowing through them when the powersupply is working under the extra load of these bad solderingpints – especially check those components which are glued with silicone to see if any silicone has seeped through the holes for the leads.

Please feel free to correct my English if that is necessary, I’m a Swede so I might have misused some words!

Did you measure the voltage at the tip of the power supply or try another power supply?

If you are getting power out of the power supply and nothing on the monitor lights up, (power LED, display, etc) then maybe the power connector on the monitor is shorted.

You could try moving the plug at the power input jack back and forth (where it’s marked “Power” in the first photgraph) while it’s plugged into the monitor and see if any lights blink. If that happens, then you know there a poor connection from the power input jack to the board.

You can take the monitor apart and look at the power input jack’s solder joints.

I had the same problems with this monitor, had called HP who gave me no hope in November 2005. I have been occasionally checking for answers [not wanting to give up on such an expensive monitor]. As it turns out HP has issued a note (somewhat hidden) that some of these monitors have a “hardware issue” which they are willing to replace (NOW). They weren’t before. I called and after an hour on the phone, they finally agreed to replace my monitor. My warranty has already expired. BUT, it is a problem that was already existent in the monitor . . . .